A magnetic storage system typically includes one or more magnetic disks with at least one data recording surface having a plurality of concentric tracks for storing data. A spindle motor and spindle motor controller rotate the disk(s) at a selected rotational velocity, typically measured in revolutions per minute (RPM), such that at least one read/write transducer or “head” per recording surface can read data from or write data to each recording surface. The data read or written from each recording surface is processed by a read/write channel. The transducer is supported by an air bearing slider that has a top surface attached to an actuator assembly via a suspension, and a bottom surface having an air bearing design of a desired configuration to provide favorable flying height characteristics. During the operation of the magnetic storage device, the air bearing slider is positioned above and in close proximity to the desired data track by an actuator assembly. The movement of the actuator assembly above the disk surface is controlled by a servo system. Such sliders have been described, e.g., in U.S. Pat. No. 5,889,637 to Chang et al., U.S. Pat. No. 5,473,485 to Leung et al, U.S. Pat. No. 5,761,003 to Sato, and U.S. Pat. No. 6,004,472 to Dorius et al.
Conventional magnetic storage systems may operate in a contact start/stop mode where the slider and transducer are only in contact with the recording surface when the spindle motor is powered down. As the disk begins to rotate, an air flow is generated which enters the leading edge of the slider and flows in the direction of the trailing edge of the slider. The air flow generates a positive pressure on the air bearing surface of the slider to lift the slider above the recording surface. As the spindle motor reaches the operating RPM, the slider is maintained at a nominal flying height over the recording surface by a cushion of air. Then, as the spindle motor spins down, the flying height of the slider drops until the slider is once again in contact with the disk.
In many conventional magnetic storage systems that operate in a contact start/stop mode, the slider drags on the disk surface until a sufficient pressure gradient is generated to lift the slider off the disk surface. This start-stop process leads to two problems at the head/disk interface: (1) wear of the disk surface (also referred to as wear durability); and (2) adhesion of the slider to the disk surface during start-up (also referred to as stiction).
One approach to circumvent the undesirable issues associated with wear durability and stiction is to use load/unload technology. Typically, load/unload technology includes a ramp for the slider/suspension assembly at the outer diameter of the disk, i.e., the landing zone, where the slider is “parked” securely while the spindle motor is powered down. During normal operation, the disk speed is allowed to reach a selected RPM (which may be below the normal operating RPM) before the head is loaded from the ramp onto the disk. As the slider approaches the disk surface, an air cushion is generated by the disk's rotation. The slider can also be unloaded from the disk's surface onto the ramp. In this manner, the slider is positioned over the disk without substantial contact with the disk surface. By reducing the contact between the slider and the disk surface, the interface life can be substantially increased. Because the slider and transducer are generally not in contact with the disk surface during start-up, stiction is not a problem. As such, a smooth (or non-textured) disk surface may be used with load/unload designs to decrease the head-to-disk spacing in order to increase the areal density of the disk.
One drawback in the use of a special landing zone is that such landing zones necessarily occupy about 5–8% of the disk surface. Thus, the disk surface cannot be employed as magnetic storage. Another drawback associated with load/unload designs is that when the slider is being “loaded” onto the disk surface, the slider may contact the disk surface before an air-bearing can be developed. This contact results in both slider wear and damage to the disk surface.
Furthermore, when the slider is being “unloaded” from the cushion of air above the disk surface onto the ramp, sliders having negative pressure air bearing designs generally resist being pulled away from the disk surface. The negative pressure region of the slider has a tendency to pull the slider toward the disk surface by a suction force as the suspension attempts to lift the slider. Eventually, the slider/suspension assembly overcomes this suction force in order to lift the slider onto the ramp. As soon as the suction force is released, the stored energy (often referred to as spring energy) within the suspension assembly causes the suspension to snap the slider away from the disk surface. This snapping motion causes the slider to oscillate or vibrate. Typically, at this point, the slider is just starting to ride up the ramp such that the corners, and possibly the edges, of the vibrating slider may contact the disk surface with sufficient force causing damage to the disk surface.
Typical sliders, including air bearing surfaces, have sharp corners and edges. One drawback of having an air bearing surface with sharp edges and corners is that during the contact start or stop, the sharp edges of the air bearing surface may cause deformations on the surface of the disk as the slider is being lifted off or placed onto the disk surface. One approach to reduce the amount of damage resulting from the slider-to-disk contact is to round the edges of the air bearing rails as shown in U.S. Pat. No. 4,928,195 to Ezaki et al. or to provide air bearing rails with beveled edges as shown in U.S. Pat. No. 5,301,077 to Yamaguchi et al. In addition, U.S. Pat. No. 5,872,686 to Dorius et al. describes an improved slider having rounded corners to minimize disk damage. In short, by rounding or beveling the air bearing rail edges, unwanted wear of the disk surface is reduced.
Rounded or beveled corners may be produced through mechanical material removal processes such as using cutting by abrasion means or through laser ablation in which high intensity light is used to evaporate material from sliders edges and corners. However, these processes only allow a few slider heads to be formed at a time and are thus economically infeasible. U.S. Pat. No. 5,997,755 to Sawada, as another example, describes a method of manufacturing a transducer with rounded corners. The patent describes an air bearing surface (ABS) and a second surface having edges at peripheries thereof formed by etching a disk-facing plane of a transducer slider. The disk-facing plane of the slider is coated with liquid resin, which is then dried. Due to surface tension effects, the resin thickness is thinner at the corners than the other portions of the ABS. After ion bombarding milling particles to the disk facing plane, the corners of the sliders are rounded. It should be evident that this method offers little if any control of the profile of the resin, and thus the corner rounding cannot be determined. Furthermore, this process is not adaptable for ABS pad edge blending.
Thus, there is a need in the art for a method for efficiently producing magnetic sliders having precisely controlled tapered edges and/or corners.